[Nontraumatic causes of bilateral avascular necrosis of the femoral head: link between hepatitis C and pegylated interferon].

BACKGROUND: Avascular necrosis of the femoral head is a frequent condition in patients with a history of trauma. The major pathologic causes include vascular diseases, malignancies, hypercoagulability states, long-term steroid treatment, and some patients have a history of hepatitis C infection treated with pegylated interferon and ribavirin. Upon studying the behavior of the hepatitis C virus, Seef, Foster and Poynard found a hypercoagulability state that causes interruption of retinacular blood flow to the femoral head, without an increased incidence of osteonecrosis in this patient group. Lauer states that such viral infections involve an autoimmune process and may result in transient vasculitides. Giampaolo, in 2005, reported the relationship between interferon use for multiple myeloma and other cancers and femoral avascular necrosis.

MATERIAL AND METHODS: Cases with a diagnosis of bilateral osteonecrosis of the femoral head were assessed.

RESULTS: Five patients were included, 4 females and one male, with a diagnosis of bilateral osteonecrosis of the femoral head. All of them had history of hepatitis C infection treated with pegylated interferon. The final diagnosis was proven by pathology after arthroplasty. A literature review was made of articles on the relationship between this condition and interferon use in patients with hepatitis C infection.

CONCLUSIONS: Finding out the relationship between viral diseases such as hepatitis B and C infection and hypercoagulability states, autoimmune processes leading to transient vasculitides and the use of pegylated interferon 2B, will help us discover new nontraumatic causes associated with this condition.